The present invention is in the general field of metallurgy and relates particularly to non-ferrous metallurgy. The invention is especially related to aluminum-silicon alloys.
It has been previously discovered, U.S. Pat. No. 2,793,949, that inorganic substances may be incorporated in metals to produce a composite material product. It is taught therein that mixtures of molten metals, including aluminum, and a large variety of inert fillers, including alumina, may be smelted together if the non-metallic material to be incorporated into the metal is wetted by the molten metal used. The wetting agents chosen are those among substances which are capable of lowering the surface tension between the metals and the materials to be incorporated therein. Such prior art also teaches that to modify the structural properties of a metal only slight amounts, less than 1 percent, say 0.1 percent, of powders or crystal materials should be added to the metal. On the other hand, when the object is to obtain, for example, abrasive compositions, the ratio of hard materials to be mixed with the molten metal should preferably exceed 50 percent by volume of the composite product and may be as high as 95 percent. Although a wide variety of metals and fillers are disclosed, no commercial success has apparently been achieved with the use of any compositions prepared by such process. Also, a number of the compositions disclosed in the reference are highly dangerous, being in fact explosive compositions.
More recently, it has been discovered that a superior aluminum composite can be prepared from aluminum, an alkaline earth metal reducing agent, such as magnesium, calcium, beryllium, sodium, potassium, rubidium or cesium, and a non-metal filler such as zircon, alumina, zirconia and aluminum silicates. See U.S. Pat. application Ser. No. 210,127 filed Dec. 20, 1971, having a common assignee with the instant invention, now abandoned.
It is therefore a primary object of the present invention to provide a new and improved aluminum-silicon alloy and composite which has sufficient strength to perform the required or desired use thereof and which is considerably less expensive than presently available aluminum-silicon alloys, especially aluminum-silicon casting alloys.
The instant invention is particularly adapted for use in the manufacture of articles wherein hardness is a principal requirement. An example of such articles are automobile engines or other engines and certain small engine parts.
It is also a primary object of the present invention to provide an aluminum-silicon alloy and composite thereof which exhibits improved properties such as tensile strength, hardness and toughness.
An important object of the present invention is to provide an aluminum-silicon composite which may be remelted and cast without any significant loss of its physical or structural properties.
Another object of the present invention is to provide a method for manufacturing an aluminum-silicon composite of material in which the physical properties may be varied over a wide range as desired, by appropriate changes in the composition.
Still another object of the present invention is to provide a new and useful aluminum-silicon composite which is substantially uniform in construction.
Other objects and advantages of the invention will become more readily apparent from a reading of the specification hereinafter.